I just replaced my old plastic distributor with a metal replacement. Even thought I marked everything I am having a hard time getting it to run right.

I have adjusted it by turning the distributor several times but is still hesitates when accelerating. Acts like it is not advancing when I put a timing light on it. Since it is electronic (1997 GMC Sierra) I have no idea how the advance works. I am an old carburetor and dwell guy.

I have gone through the plugs and vacuum lines but haven't found anything wrong yet. Hope someone can help!

 

You can't time a vortec with a timing light. The pcm and crank position sensor control spark. You'll find several write ups that can explain it better than I can. Just Google vortec timing.

 

I finally found some good information about it. Said I need to have a mechanic use a scan tool to set timing and "re-learn" the computer.

 

Well, according to the dealer mechanic, there is nothing they can do because I installed the distributor 1 or 2 teeth off. So, how can it still be running if I got it that far out? Let alone I marked everything and the new distributor went in the same way the old one came out.

Any ideas?!?

 

line up timing marks on harmonic balancer,, pull distributor and put back in lining up the rotor with no. 1. you may have to use long screwdriver to turn oil pump shaft to match. If it backfires, you are 180 degrees out. if that happens, pull distributor and rotate 180 degrees, you should be set.

 

I had a similar situation (and fix) with my 1999 Vortex. Are you getting any codes? What brand replacement distributor?

 

ac delco distributor. no codes . wont start or run . shut it off and just wont start. guy just told me to try the electronic spark control module. that sounds like a possibility. what fixed yours?

 

I replaced the crap plastic GM distributor with a billet MSD replacement unit. It did not line up perfectly with the original distributor. The truck was running, but poorly, and I had a code for a timing problem. Rather than pay the dealer for time with a Tech 2, I marked the current distributor location with a pointer attached to the distributor and made a mark on a piece of masking tape I put on the firewall. From there, it was a process of turning the distributor about one-eighth of an inch at a time, based on the extended pointer location on the firewall. After each new location, if I still got the trouble code, I cleared it and turned the distributor another eighth of an inch. After a few tries, I got to the point where the code no longer was thrown at the new distributor location, so I just tightened it down and was good to go for several thousand miles until I sold the truck. The tolerance on the distributor setting was plus or minus two degrees, and when you get it in that spot, all is well.

 

I'll have to go somewhere again to read the codes. I did put the #1 piston up and moved the distributor a couple of teeth. It is running better but still not dead on. Seems to run OK but rough on acceleration. Just need to mess with it a bit more.

 

Time for another update. I went to a local garage and got some advice from the mechanic. The old and new distributors were a half a tooth off from each other.

Took the shaft out of the new distributor and put the old shaft and gear in it. That solves my alignment problem! So now, I have a metal distributor with good cap screw holes and no timing issues.